Thanks for the ideas and advice, it became very clear once in the resort that you don't have to look far to find a WG in Marbella! I stayed in what is supposed to be the best hotel in the resort and all of the single women in the bars were working the joint.
After a few beers down in Puerto Banus we landed in the Navy Bar and for those that have never been, the girls are charged €30 entry and then they work the room all night long, to get their entry fee back and earn their cash. They are nothing special and if anything its about as bad as punting can get a real meat market.
A word of caution, 2 or 3 of our group were mugged by the working girls on the street, they arrive mob handed and start grabbing your trousers rubbing your crotch etc and whilst they are doing this they slip your wallet out of your back pocket and then just scatter into the night.